3 months in Southeast Asia in February

Hi everyone!
Me and my friend will arrive in Bangkok in the beginning of February and will travel through Thailand, Myanmar, Laos, Vietnam and Cambodia (at least that is the plan...) for about 3 months. We have been planning this for a while and we know about plenty of things we want to do but I just wanted to see if you can recommend some places or activities that aren't the "typical tourist things". We have plenty of time and won't be in a rush. Basically we want to know about a lot of places and activities and when it comes to it we just want to go with the flow and do what we feel like, but it's always better to be prepared and know what you are doing! :)

So if you have any special tips, or know about something awesome going on somewhere while we are travelling, please share!! :)